Don't worry. the following points can please be followed for corrective & preventive
1. Simple mails that you were missing them for while due to your personal limitations.
2.Keep writing them simple mails personally for a while at regular interval till you see them responding either by login to SFI or to your mail
3.Motivate them to contact you any time to ensure that you extend your fullest support as a sponsor
4.Collect & store all the contact details of your affiliates like mail, phone, messenger id so that you can contact them through your iphone when you are travel, out from your home, office in any one mode
5. In future, ensure you are collecting all the contact details from your affiliates either at registration(PSA) stage or after registration/allocation(CSA).